This box will require a firm table for its support during the etching, said table standing as close as convenient to a sink and water tap.
The other requisites used during etching, are, nitric acid, turpentine, gum Arabic of a good quality, some powdered nutgalls, three or four sponges, some finely powdered resin, a flat camel’s-hair brush, a solution of shellac in spirits of wine, and the following inks:
First the etching ink, composed of beeswax one-quarter ounce, Russian tallow two ounces, bitumen half an ounce, middle varnish two ounces.
Melt these together in a pan over a fire, or Bunsen burner, stirring well during the operation, so as to mix them thoroughly; when all are melted, add five ounces of ordinary letterpress printing-ink, and thoroughly mix; then allow to boil and continue the heat until the gas escaping from the bursting bubbles explodes upon the application of a lighted taper; then remove all from the fire, and allow to cool.
For a hard ink, for use after the plate is etched deep enough, and the resist is cleaned off, mix
| Beeswax | 1⁄2 | ounce. |
| Resin | 1 | ounce. |
| Shoemaker’s Wax | 1 | ounce. |
| Black Litho Ink (about $1 a pound) | 2 | ounces. |
Melt, then cool and mix with turpentine to make it the consistency of soft soap.
Now, with these and a solution of gum Arabic (in cold water), the thickness of cream, add one-quarter pint of a decoction of nutgalls to each quart of gum solution. The decoction of nutgalls is made by adding one-quarter pound of bruised nutgalls to one and one-half pints of water, in an earthenware vessel (not metal); boil, then allow to stand at the fire and simmer gently for six hours, keeping the vessel covered over; then allow to cool, filter and add the proper quantity to the above gum solution.
We will assume that a suitable place is provided for carrying on the operations to be described, in the shape of plenty of bench room, and a good light to work by.
The first stage in etching a zinc plate in relief is, to slightly warm it upon the hot plate, then allow it to cool (by-the-bye, it will be very convenient to have a clean litho stone handy for placing the plate upon to cool quickly). The plate being cold, with a piece of soft sponge carefully smear it over with the gum solution, allow the gum to dry, spontaneously, in a cold current of air; if heat be applied the gum will crack and bring away the image from the plate.